Almost everybody uses the multistage extension, and having it in a
sepate gem has never really made that much sense. With this commit you
can use multistage by requiring `capistrano/ext/multistage`. The Gem
`capistrano-ext` no longer required.

This renames the task `deploy:symlink` to `deploy:create_symlink`.
This will break any before/after hooks and callbacks. Please update
your recipes accordingly.
This is a rather unfortunate side effect of the widening Rake API
and bad namespacing behaviour on both their side and ours. If you
cannot make the upgrade, please lock the Capistrano version in your
Gemfile at a suitable, earlier version.

Don't dereference symlinks when deploying via copy.
(allows for absolute symlinks… this commit might cause problems, but there haven't been any comments on the issue request, and it will help at least one person.)

Capistrano outputs all logs into a single place which makes it rather difficult
to figure out what has happened on a single host machine, especially when you are
running parallel. By adding host information to the log as possible as it can will
enable tools such as splunk to easily filter out host specific log information, which
is helpful during the later auditing process.